Top-quark forward-backward asymmetry from a color-octet t-channel resonance

Abstract

We consider new physics contributions to the top-quark forward-backward asymmetry from a neutral $V_8^0$ or charged $V_8^{+}$ color-octet vector exchanged in the $t$-channel. We study the phenomenological constraints on these particles arising from the Tevatron and LHC7 measurements and compare them with those on their color singlet counterparts $Z^{\prime }$ and $W^{\prime }$. We find that the color octets fare better than the singlets in that they generate a lower $A_C$, a lower high-invariant mass cross-section at LHC7 and a lower same sign top-pair cross-section. However, they also generate a lower $A_{FB}$ than their color-singlet counterparts.

Comments: References added and corrected, typos fixed